Thanks Shawn, the first part in CLASSES_ROOT didn't show in the registry, although the TMP file was restored to what appeared normal.
Windows Registry Editor Version 5.00
; Created by: Shawn Brink
;
http://www.vistax64.com
; Tutorial:
Default File Type Associations - Restore
[-HKEY_CLASSES_ROOT\.tmp]
[-HKEY_CLASSES_ROOT\SystemFileAssociations\.tmp]
[-HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.tmp]
So I edited it to this.
[HKEY_CLASSES_ROOT\.tmp]
[HKEY_CLASSES_ROOT\SystemFileAssociations\.tmp]
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.tmp]
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.tmp\OpenWithList]
Did I do right? the TMP file still appears restored to default.